First, yesterday Treehugger reported on the new Citroen C2 with "stop/start technology" that cuts the engine when the driver steps on the brakes, and restarts it within 400 milliseconds of letting up on the brakes. In addition to the gasoline savings this will provide, Citroen is also offering a "a cashback incentive of £1,696 (US$2,963, "sufficient to cover one year's London Congestion Charge") to buyers of the new C2 Stop & Start." And, the price of the car is reasonable: £10,690 (US$18,674), not including the cashback incentive. (see also Green Car Congress)

I'm sure I need not point out that it seems contrary to Citroen's goal implicit message (thanks, Donal) to offer the cashback savings that's no-so-coincidentally the same as London's congestion charge.